a. Field of the Invention
This invention relates to an operating pedal for a power transmission in a motorcycle, and, more particularly, it is concerned with such a power transmission operating pedal which can be bent or collapsed only in the rearward direction to avoid any shock to the vehicle even when the pedal hits an obstacle such as stone, wooden block, etc. during running of the vehicle.
b. DESCRIPTION OF PRIOR ARTS
Various constructions of collapsible operating pedal for the power transmission in the motorcycle have heretofore been proposed.
For example, laid-open Japanese utility model application No. 50-6049 discloses a pedal reinstating device in a motorcycle, in which a pedal arm is fixedly connected at one end thereof with a rotational shaft provided at a lower part of the motorcycle body, and is pivotally connected at its other end with an operating pedal. Within this pedal a cylindrical recess is formed in its axial direction facing the mutual slide contacting surface between this tip end of the pedal arm and the pedal, into which a pressure piece is fitted in one direction, and a resilient member to bias this pressure piece toward the other direction is accommodated in this cylindrical recess. At the same time, a fitting part is formed in the tip end of the pedal arm at a position rightly opposite to the pressure piece to enable the same to fit slidingly into this fitting part, and a cam surface is further formed in the shape of a smoothly curved continuous surface from this fitting part. This cam face is formed in such a manner that a distance from the pivotal point of the pedal arm and the pedal may be gradually lengthened as the cam face is away from the fitting part.
Another laid-open Japanese utility model application No. 50-39946 discloses a change pedal for a motorcycle, in which the base end of a change lever is fitted onto a rotational shaft projected from the lateral side of an engine casing, a vertical shaft is provided at the other end of the change lever, to which the base end of the pedal is pivotally fitted, and the pedal is energized by a spring provided around the vertical shaft so that it may always be kept at its normal position.
Further, laid-open Japanese patent publication No. 53-1710 discloses a change pedal for a motorcycle, in which one end of a change pedal having holes formed therein is pivotally connected by means of a tightening bolt and nut with one end of an operating lever through holes perforated therein, and a spring having supporting legs is fixed on a pin held in other holes formed in the medal, whereby the pedal may possibly be collapsed in the rearward direction when it hits an obstacle.
The change pedals for the motorcycle of the conventional structure as has been stated in the forgoing are generally of such construction that the spring is provided around a rotational shaft of the pedal, on account of which a cavity is required to be formed in the body of the pedal. Consequently, the rotational shaft has small contact arms with the bearing surface of the pedal along its whole length as well as in entire periphery. In other words, since no sufficient bearing surface is secured with the rotational shaft, there is high possibility of the pedal and the rotational shaft becoming loose and shaky owing to their use over a long period of time.